The present disclosure generally relates to luminescent solar collectors. In particular, it relates to methods of increasing the concentration of light at the edge of such a solar collector to produce enhanced amounts of electrical power.
Luminescent solar collectors (LSCs), or luminescent solar concentrators, are beneficial for capturing solar energy for use. An LSC usually comprises a sheet, generally a molded polymer, having a surface area. Dispersed, dissolved, or doped within the sheet is a fluorescent material. When the sheet is exposed to light (radiation energy), the material absorbs a portion of the light and emits the absorbed light energy at different, longer wavelengths. This light is then transported, via total internal reflection, to at least one edge of the sheet. The concentration of light from a large surface area to a smaller surface area (the edge) is also known as the “edge glow” effect. Due to this effect, the amount of light (i.e. energy) available at the edge is related to the total surface area of the sheet. A light energy converter, such as a silicon photocell, can be attached to at least one edge of the LSC to convert the light energy transmitted thereto into electricity. This enables the LSC to concentrate the maximum amount of light at its edge or edges to generate more electrical power.
One type of fluorescent material used in luminescent solar collectors is Lumogen® F Red 300, commercially available from BASF. However, Lumogen® F Red 300 poorly absorbs wavelengths around 480 nanometers at lower concentrations. It would be desirable to capture light energy around these wavelengths as well to increase the efficiency of the LSC by increasing the amount of electrical power produced with the same surface area. In addition, these wavelengths give the LSC a red color to the human eye and also allow the LSC sheet to be somewhat visibly transparent. Capturing this energy would reduce the red color of the LSC sheet and make the LSC sheet more opaque, resulting in the better shielding of structural and accessory features, such as connection materials, wiring, etc., from view.